Head space

Just racked to secondary after 8 days and I have a bit of head space. I've noticed a lot of people in threads topping off with juice. So my question is, how much space is to much and if my final gravity is where I want it what can I do to get it back down or is that even possible? Here's a pic

My personal opinion is that some headspace isn't the end of the world but that depends on where the fermentation is at and what you started with. If you are making apple wine, I'd top it up and let the yeasties do their thing to put a fresh new blanket of CO2 in there. If your gravity hasn't dropped off too much and there's still yeasties in there making CO2, you might be ok. (I'm sure most people won't agree with that though) If you are going to let it sit for an extended period of time without topping it off, someone might give you advice on using Potassium Metabisulfite to help with oxidization.

Potassium Metabisulfite is the same thing as Campden right? I just used some on another batch and when I crushed the tablets up after almost a week they were still floating along the edge of the jug, even after several swirls. Would it be better to just add more juice and hope for the best taste wise?

OK, here goes:
I am new to brewing, but I am an experienced chemist. Considering the time, effort, and money that each batch represents, you/we should view every batch as an experiment. Control as many variables as you are able, learn as much as you possibly can; take detailed notes.
Probably, as I plan to do, you will have a stock 'house brew' for everyday 'use', and your other batches will be experimental. In each case, you want to get out of a batch at least as much as you put into it. Errors are bad, but errors whose causes are unknown are MUCH worse..
Re: Headspace; Oxygen is 23% of the atmosphere/headspace, and when it is present, yeast grow aerobically: they prefer to eat alcohol and make vinegar.
Enough theory: Either use a vessel of appropriate size(losing liquid to foam is better than losing flavor in an entire batch), or try this in an emergency: cleanse a thin poly bag both sides and stuff it into the vessel(opening to stay outside the vessel! yes, like a bladder), inflate it with clean, filtered air until it fills the headspace. I'm not saying the bag is not permeable to oxygen, but at least you have SOME barrier until the yeasties can generate a CO2 blanket. Yes, you have to watch it. Good luck.

AlCophile said:

cleanse a thin poly bag both sides and stuff it into the vessel(opening to stay outside the vessel! yes, like a bladder), inflate it with clean, filtered air until it fills the headspace. I'm not saying the bag is not permeable to oxygen, but at least you have SOME barrier until the yeasties can generate a CO2 blanket. Yes, you have to watch it. Good luck.

Click to expand...

Nice, like a homemade variable capacity tank!
I really like this idea.

Mylar is less permeable for a long-term storage solution in an oversized carboy. Inflate with a straw then rubber-band around the neck. Simple, cheap, effective.

(losing liquid to foam is better than losing flavor in an entire batch),

My last two batches have had a lot of foam/krausen (spelling) so I have had to syphon off which lowered the amount of cider, and then syphoning off the yeast has lowered even more. Just wondering if maybe I was doing something wrong or that's just the way it is. I had someone mention sanitized marbles to fill the space. I think I might just ferment longer next time and add more juice if needed. Thanks for the info, and every batch of cider I makes is a learning experience with lots of note taking.